Comparison of optical fiber Bragg grating hydrogen sensors with Pd-based thin films and sol-gel WO3 coatings

Pd-based thin films and sol-gel WO3 coatings are two kinds of hydrogen sensitive elements used in hydrogen concentration sensing and detection. Optical fiber hydrogen sensors are very promising solutions for flammable hydrogen detection, when the sensitive materials are integrated with optical fiber sensors. This paper reviews the sensing performance of optical fiber hydrogen sensors with these two sensitive materials, which are developed at the National Engineering Laboratory for Optical Fiber Sensing Technologies in Wuhan University of Technology.